Printed circuit board and pad apparatus having a solder deposit

Abstract

A printed circuit board and a pad apparatus having a solder deposit formed on the pad apparatus by using a mask having a slit are provided. The slit has the same shape as the solder deposit. The solder deposit includes first and second end portions individually shaped and sized to completely cover at an end portion of the pad a predetermined area of an end portion of the pad, the area defined by both the entire width of the pad and a predetermined length from the end of the pad. A connection web extends between the two end portions to integrate the two end portions into a single structure and is a longitudinal part having a width smaller than any one of both the width of the pad and the width of each of the two end portions. First and second trapezoidal portions are respectively formed at junctions between opposite ends of said connection web and one of the two end portions. The mask has a slit formed at a position corresponding to the position of the solder deposit. This slit includes first and second end opening parts corresponding to the two end portions of the solder deposit, a web opening part corresponding to the connection web, and first and second trapezoidal opening parts respectively formed at junctions between opposite ends of said web opening part and said two end opening parts and corresponding to the first and second trapezoidal portions of the solder deposit.

What is claimed is:  
     
       1. A printed circuit board, comprising: 
       a board;  
       a pad formed on one surface of said board; and  
       a solder deposit formed on said pad, said solder deposit including:  
       a plurality of end portions having a first width;  
       a middle portion connected between said end portions, having a second width narrower than said first width of said end portions; and  
       a plurality of tapered portions having a third width gradually varying from said first width to said second width, each connected between one of said end portions and one end of said middle portion.  
     
     
       2. The printed circuit board of  claim 1 , said tapered portions having a first side line having an angle ranging 42 degrees to 48 degrees with respect to a second side line of said middle portion. 
     
     
       3. The printed circuit board of  claim 1 , said pad having a fourth width greater than or equal to any one of said first width, said second width, and said third width. 
     
     
       4. The printed circuit board of  claim 1 , said pad having a length greater or equal to a sum of lengths of said end portions, said middle portion, said tapered portions. 
     
     
       5. The printed circuit board of  claim 1 , said solder deposit being made of a conductive single body. 
     
     
       6. The printed circuit board of  claim 1 , said solder deposit comprising a solder formed on an entire area of said solder deposit with a predetermined thickness. 
     
     
       7. The printed circuit board of  claim 1 , said solder deposit comprising a rounded portion between said middle portion and said tapered portion. 
     
     
       8. The printed circuit board of  claim 1 , said solder deposit comprising a rounded portion between one of said tapered portions and one of said end portions connected to said one of said tapered portions. 
     
     
       9. The printed circuit board of  claim 1 , said middle portion comprising a length greater than said second width. 
     
     
       10. The printed circuit board of  claim 1 , said middle portion having said second width greater than or equal to a half of said first width. 
     
     
       11. The printed circuit board of  claim 1 , said middle portion having said second width less than or equal to a half of said first width. 
     
     
       12. The printed circuit board of  claim 1 , said tapered portions having a trapezoidal shape. 
     
     
       13. The printed circuit board of  claim 1 , said tapered portions being the same shape as a cross section of a frustum. 
     
     
       14. The printed circuit board of  claim 1 , said tapered portion including a curved line formed between said middle portion and one of said end portion. 
     
     
       15. The printed circuit board of  claim 1 , further comprising at least one nonconductive portion formed on said pad, disposed outside said solder deposit. 
     
     
       16. The printed circuit board of  claim 15 , said nonconductive portion formed between side lines of said tapered portions, disposed outside said middle portion. 
     
     
       17. The printed circuit board of  claim 1 , further comprising an electronic device having at least one lead, a distal end of said lead disposed within said middle portion of said solder deposit. 
     
     
       18. The printed circuit board of  claim 17 , said solder deposit disposed within said pad without flowing over outside said pad after soldering said lead to said pad. 
     
     
       19. The printed circuit board of  claim 17 , said second width of said middle portion greater than a fourth width of said lead of said electronic device. 
     
     
       20. The printed circuit board of  claim 17 , said distal end having a length less than said middle portion. 
     
     
       21. The printed circuit board of  claim 1 , further comprising a semiconductor having at least one lead, a distal end of said lead disposed on said middle portion and said tapered portions of said solder deposit. 
     
     
       22. The printed circuit board of  claim 1 , further comprising a mask disposed above said board to form said solder deposit, said mask having a slit having end openings corresponding to said end portions and middle opening corresponding to said middle portion. 
     
     
       23. The printed circuit board of  claim 22 , further comprising tapered openings each corresponding to tapered portions having a third width gradually varying said first width to said second width, said tapered portions each disposed between one of said end portions and one end of said middle portion to couple said middle portion to said end portions. 
     
     
       24. The printed circuit board of  claim 22 , said mask removed from said board after a solder is applied to said pad through said slit of said mask to form said solder a deposit. 
     
     
       25. A printed circuit board, comprising: 
       a board;  
       a conductive pad formed on a surface of said board and used for mounting a lead of an electronic device on said board, having a first width and a first length; and  
       a solder deposit formed on said conductive pad and used for electrically connecting a distal end of said lead of said electronic device to said conductive pad, said solder deposit comprising:  
       a first end portion covering a first end area of said pad, said first end area defined by both an entire said first width of the pad and a predetermined length of said first length from a first end line of said pad;  
       a second end portion covering a second end area of said pad opposite to said first end portion, said second end area defined by both an entire said first width of said pad and a predetermined length of said first length from a second end line of said pad;  
       a connection web extending between said first and second end portions, integrating said two end portions into a single structure, having a second width smaller than any one of both said first width of said pad and a second width of each of said two end portions; and  
       first and second trapezoidal portions each formed at each junction between said connection web and one of said two end portions, each having two tapered sides.  
     
     
       26. The printed circuit board of  claim 25 , said first and second trapezoidal portions each having a side line having an angle ranging 42 degrees to 48 degrees with respect to a longitudinal side line of said connection web. 
     
     
       27. The printed circuit board of  claim 25 , said connection web having a length corresponding to a length of said lead of the electronic device mounted to the pad. 
     
     
       28. The printed circuit board of  claim 25 , further comprising a mask disposed above said board to form said solder deposit, said mask having a slit having end openings corresponding to said end portions and middle opening corresponding to said connection web. 
     
     
       29. The printed circuit board of  claim 25 , further comprising a mask disposed above said board to form said solder deposit and removed after forming said solder deposit, said mask having a slit having end openings corresponding to said end portions, middle opening corresponding to said connection web, and first and second trapezoidal openings corresponding to said first and second trapezoidal portions. 
     
     
       30. The printed circuit board of  claim 29 , said first and second trapezoidal portions each having a side line having an angle ranging 42 degrees to 48 degrees with respect to a longitudinal side line of said connection web. 
     
     
       31. A method, comprising the steps of: 
       providing a printed circuit board having a pad;  
       providing a mask having a slit formed on said mask, said slit having two end openings, a middle opening disposed between said end openings, and two tapered openings each disposed between said middle opening and one of said end openings;  
       locating said printed circuit board below said mask so as to dispose said slit within said pad;  
       applying a solder to said pad through said slit of said mask; and  
       forming a solder deposit on said pad, said solder deposit including first and second end portions covering first and second end areas of said pad and corresponding to said end openings, a connection web extending between said first and second end portions, integrating said two end portions into a single structure, and having a second width smaller than any one of both said first width of said pad and a second width of each of said two end portions, and first and second trapezoidal portions each formed at each junction between said connection web and one of said two end portions, each having two tapered sides.